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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Near surface stress measurements in a candidate rock mass for superconductive magnetic energy storage

Fischer, Dennis J. January 1982 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 127-133).
92

Temperature dependent control of community energy storage devices

Fuller, Jason C. January 2010 (has links) (PDF)
Thesis (M.S. in electrical engineering)--Washington State University, May 2010. / Title from PDF title page (viewed on July 15, 2010). "School of Electrical Engineering and Computer Science." Includes bibliographical references (p. 71-75).
93

Geologic factors in siting tunnels for superconductive energy storage magnets

Doe, Thomas William, January 1980 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1980. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 233-245).
94

Switching converter techniques for energy harvesting applications /

Sze, Ngok Man. January 2007 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 93-95). Also available in electronic version.
95

Carbon cryogel based nanomaterials for efficient energy storage /

Feaver, Aaron. January 2007 (has links)
Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 196-206).
96

Fabrication and inorganic modification of 3D carbon nanotube structures for applications in energy storage

Jessl, Sarah January 2018 (has links)
Structured electrodes with tailored nanoscale morphology and chemistry are highly desirable for a range of applications. In particular, emerging energy storage applications such as thick Lithium-ion battery (LIB) electrodes and photoanodes for watersplitting require new electrode structures that simultaneously optimise electron, ion, and thermal transport. In this PhD thesis, advanced structured electrodes are fabricated by creating 3D carbon-inorganic hybrid architectures. In this process, patterned vertically aligned carbon nanotubes (CNT) were used as the structural scaffolds to shape the electrodes while inheriting the excellent thermal and electrical properties of CNTs. First, UV and colloidal lithographic patterning processes were developed to create micro- and nanopores respectively within the CNT structures. Those structures provide high surface area and conductive backbone for the synthesis of hybrid CNT-inorganic structures. Specifically, the parameter space to create honeycomb shaped CNT structures with pores ranging from 300~nm to 30~$\mu$m has been established. Next, the micro-pore CNT structures have been chemically modified with iron oxide using microwave-assisted, hydrothermal synthesis for fabricating high areal loading LIB anodes. The areal loading was increased by 120\% compared to a standard battery film while at the same time retaining a high capacity (900 mAhg$^{-1}$ at 0.2 C). Then thick electrodes with optimised diffusion pathways were created by coating the nanopatterned CNTs with silicon using physical vapour deposition. These electrode structures are up to 50\% thicker than previously reported structures and still retain a stable capacity (650 mAhg$^{-1}$) and a good high-rate performance. Finally, the honeycomb shaped CNT structures have been coated with bismuth vanadate using a hotcasting process and the electrode architecture has been optimized for good conductivity by the addition of a Pd/Au layer between the CNTs and the BiVO$_{4}$. The photoelectrode performance was measured and shows a clear increase in current density when exposed to light. Each of these novel electrodes illustrate how patterning vertically aligned carbon nanotube structures combined with inorganic surface modification enables the creation of advanced electrodes with new formfactors and improved performance in comparison to literature and to classic drop-casted battery films of the same materials.
97

Evaluation of Battery Performance in MMC based BESS

January 2018 (has links)
abstract: Li-ion batteries are being used on a large scale varying from consumer electronics to electric vehicles. The key to efficient use of batteries is implementing a well-developed battery management system. Also, there is an opportunity for research for improving the battery performance in terms of size and capacity. For all this it is imperative to develop Li-ion cell model that replicate the performance of a physical cell unit. This report discusses a dual polarization cell model and a battery management system implemented to control the operation of the battery. The Li-ion cell is modelled, and the performance is observed in PLECS environment. The main aspect of this report studies the viability of Li-ion battery application in Battery Energy Storage System (BESS) in Modular multilevel converter (MMC). MMC-based BESS is a promising solution for grid-level battery energy storage to accelerate utilization and integration of intermittent renewable energy resources, i.e., solar and wind energy. When the battery units are directly integrated in submodules (SMs) without dc-dc interfaced converters, this configuration provides highest system efficiency and lowest cost. However, the lifetime of battery will be affected by the low-frequency components contained in arm currents, which has not been thoroughly investigated. This paper investigates impact of various low-frequency arm-current ripples on lifetime of Li-ion battery cells and evaluate performance of battery charging and discharging in an MMC-BESS without dc-dc interfaced converters. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2018
98

An Investment Planning Model for a Battery Energy Storage System - Considering Battery Degradation Effects

January 2014 (has links)
abstract: As global energy demand has dramatically increased and traditional fossil fuels will be depleted in the foreseeable future, clean and unlimited renewable energies are recognized as the future global energy challenge solution. Today, the power grid in U.S. is building more and more renewable energies like wind and solar, while the electric power system faces new challenges from rapid growing percentage of wind and solar. Unlike combustion generators, intermittency and uncertainty are the inherent features of wind and solar. These features bring a big challenge to the stability of modern electric power grid, especially for a small scale power grid with wind and solar. In order to deal with the intermittency and uncertainty of wind and solar, energy storage systems are considered as one solution to mitigate the fluctuation of wind and solar by smoothing their power outputs. For many different types of energy storage systems, this thesis studied the operation of battery energy storage systems (BESS) in power systems and analyzed the benefits of the BESS. Unlike many researchers assuming fixed utilization patterns for BESS and calculating the benefits, this thesis found the BESS utilization patterns and benefits through an investment planning model. Furthermore, a cost is given for utilizing BESS and to find the best way of operating BESS rather than set an upper bound and a lower bound for BESS energy levels. Two planning models are proposed in this thesis and preliminary conclusions are derived from simulation results. This work is organized as below: chapter 1 briefly introduces the background of this research; chapter 2 gives an overview of previous related work in this area; the main work of this thesis is put in chapter 3 and chapter 4 contains the generic BESS model and the investment planning model; the following chapter 5 includes the simulation and results analysis of this research and chapter 6 provides the conclusions from chapter 5. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2014
99

Packed-bed rock thermal energy storage for concetrated solar power: enhancement of storage time and system efficiency

Maidadi, Mohaman Bello January 2013 (has links)
Solar thermal energy harvesting is a promising solution to offset the electricity demands of a growing population. The use of the technology is however still limited and this can most likely be attributed to the capital cost and also the intermittent nature of solar energy which requires incorporation of a storage system. To make the technology more attractive and effective, cheap means of harvesting solar energy and the development of efficient and inexpensive thermal energy storage devices will improve the performance of solar energy systems and the widespread use of solar energy. Heat storage in a packed-bed rock with air as the working fluid presents an attractive and simple solution for storing solar thermal energy and it is recommended for solar air heaters. A packed-bed rock storage system consists of rocks of good heat capacity packed in a storage tank. The working fluid (air) flows through the bed to transfer its energy. The major concern of the design for a packed-bed rock thermal storage system is to maximize the heat transfer and minimise the pressure drop across the storage tank and hence the pumping power. The time duration the stored energy can be preserved and the air flow wall effect through the bed are the common complications encountered in this system. This study presents an experimental and analytical analysis of a vacuum storage tank with the use of expanded perlite for high temperature thermal energy storage in a packed-bed of rocks. Dolerite rocks are used as the storage medium due to their high heat capacity and as they are locally available. To minimise the pressure drop across the tank, moderate rock sizes are used. The tank contains baffles, allowing an even spread of air to rock contact through the entire tank, therefore improving heat transfer. There is a good correlation between the predicted and the actual results (4 percent) which implies that the baffles incorporated inside the vacuum tank forces the air through the entire tank, thereby resulting in an even lateral temperature distribution across the tank. The investigation of heat loss showed that a vacuum with expanded perlite is a viable solution to high temperature heat storage for an extended period. The research also focuses on the investigation of a proposed low cost parabolic trough solar collector for an air heating system as shown in Figure (1.3). The use of a standard solar geyser evacuated tube (@R130 each) has cost benefits over the industry standard solar tubes normally used in concentrating solar power systems. A mathematical was developed to predict the thermal performance of proposed PTC and it was found that the measured results compared well with the predictions. The solar energy conversion efficiency of this collector is up to 70 percent. This research could impact positively on remote rural communities by providing a source of clean energy, especially for off-grid applications for schools, clinics and communication equipment. It could lead to a significant improvement in the cost performance, ease of installation and technical performance of storage systems for solar heating applications.
100

Thermoelectrochemical model for RFB with an application at a grid level for peak shaving to reduce cost of the total electricity

Magallanes Ibarra, Laura 04 January 2021 (has links)
Reliable, low-cost energy storage solutions are needed to manage variability, pro-vide reliability, and reduce grid-infrastructure costs. Redox flow batteries (RFB) area grid-scale storage technology that has the potential to provide a range of services.Desirable characteristics are long cycle life, high efficiency, and high energy density.A key challenge for aqueous redox flow battery systems is thermal sensitivity. Oper-ating temperature impacts electrolyte viscosity, species solubility, reaction kinetics,and efficiency. Systems that avoid the need for active thermal management whileoperating over a wide temperature range are needed. A promising RFB chemistry isiron-vanadium because of the use of low-cost iron. This is an analysis of the thermalresponse of on Iron-Vanadium (Fe/V) RFB using a zero-dimensional electrothermalmodel. The model accounts for the reversible entropic heat of the electrochemicalreactions, irreversible heat due to overpotentials, and the heat transfer between thestack and environment. Performance is simulated using institutional load data forenvironmental conditions typical of Canadian jurisdictions. / Graduate

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